Megalichthyidae
Ectosteorhachis, reconstruction drawing
- Germany, Norway, Turkey, Siberia
- Utah ( USA)
- Queensland (Australia)
- Antarctic
The Megalichthyidae are an extinct family of flesh -finned fishes ( Sarcopterygii ), which occurred from the Upper Devonian to Lower Permian.
Features
Synapomorphies that diagnose the taxon, are elongated or slit- shaped outer nostrils, which are partially enclosed by a back bone. The rear lying between the Maxillaria outgrowth of the intermediate jaw ( premaxilla ) carries tusks. The vomer ( vomer ) is short and broad and sometimes has a strong mesial outgrowth on. The lacrimal bone ( lacrimal ) has a well-developed notch. The parietal ( parietal ) is notched so as to enclose the rear nose ( nasal ). Last feature is not universally accepted, as it is of variable severity.
Genera
- Cladarosymblema ( Lower Carboniferous, Fox, Campbell, Barwick & Long, 1995)
- Ectosteorhachis ( Carboniferous to Permian, Cope, 1880)
- Lohsania ( Lower Permian of Utah, Thomson & Vaughn, 1968)
- Mahalalepis? ( Middle Devonian of Antarctica, Young et al., 1992)
- Megalichthys ( Carboniferous to Permian, Agassiz, 1835)
- Megapomus ( Middle Devonian of Russia, Vorobyeva, 1977)
- Megistolepis ( Upper Devonian of Siberia, Obruchev, 1955)
- Palatinichthys ( Lower Permian of Germany, Witz et al., 2012)
- Sengoerichthys ( Upper Devonian of Turkey, Janvier et al., 2007)
System
The Megalichthyidae were formerly placed in the order today regarded as paraphyletic Osteolepiformes. Today they form the order Megalichthyiformes, which is the sister group of the Eotetrapodiformes, emerged from the finally the land vertebrates ( Tetrapoda ) together with the genera Gogonasus, Gyroptychius, Medoevia and Osteolepis.
The systematic position cladogram shows the following:
Kenichthys
Rhizodontidae
Gogonasus
Gyroptychius
Osteolepis
Medoevia
Megalichthyidae
Tristichopteridae
Tinirau
Platycephalichthys
Elpistostegalia → terrestrial vertebrates ( Tetrapoda )